Horstmann G A, Dietz V
Department of Clinical Neurology and Neurophysiology, University of Freiburg, F.R.G.
Neurosci Lett. 1988 Dec 19;95(1-3):179-84. doi: 10.1016/0304-3940(88)90653-2.
An experiment was designed to evaluate the vestibular contribution to the stabilization of upright stance in normals and in two patients with loss of vestibular function. A forward or backward displacement of a load (2 kg) by a torque motor attached to the subject induced opposing movements in the head and trunk. The small linear acceleration of the head in space of about 0.1 g was followed, with a latency of 50-65 ms, by EMG responses in the tibialis anterior and rectus femoris (backward acceleration) or gastrocnemius muscles (forward acceleration). These responses were absent in patients with a vestibular deficit. It is suggested that the observed EMG responses are due to fast acting vestibulospinal reflexes involved in the regulation of upright stance. For comparable head accelerations the integrated EMG responses induced by the vestibulospinal mechanism are about ten times smaller than those induced by spinal stretch reflexes during displacement of the feet. Vestibulospinal reflexes would appear, therefore, to play only a minor role in the compensation of stumbling.
设计了一项实验，以评估前庭对正常人和两名前庭功能丧失患者直立姿势稳定的贡献。通过连接在受试者身上的扭矩电机使负载（2千克）向前或向后位移，会引起头部和躯干的反向运动。头部在空间中约0.1g的小线性加速度之后，胫前肌和股直肌（向后加速度）或腓肠肌（向前加速度）会出现潜伏期为50 - 65毫秒的肌电图反应。在前庭功能缺失的患者中没有这些反应。有人认为，观察到的肌电图反应是由于参与直立姿势调节的快速作用的前庭脊髓反射。对于相当的头部加速度，在前庭脊髓机制诱发的肌电图反应中，与在足部位移期间由脊髓牵张反射诱发的反应相比，前者要小约十倍。因此，前庭脊髓反射在绊倒补偿中似乎仅起次要作用。
